Water

Water

1. Function

   • 1. Regulation of body temperature: By cooling body during hot weather or strenuous activities. When temperature in body rise, the sweat glands in skin start to secrete sweat onto surface of skin. As sweat evaporates from skin, produces cooling effect. Thus, excess body heat is removed through perspiration
   • 2. Removal of waste products: Most waste products made by body are water-soluble and can be excreted from urine, which is mostly made up of water. Water also helps to add bulk to our solid waste materials, also lubricates colon to allow easier removal of waste materials and prevent constipation.
   • 3. Lubrication of joints and organs: Joints are protected by cartilage and synovial fluid which are composed mainly of water. They help to absorb shock and promote smooth join actions. Water is also needed to moisten the food we eat, protect the linings of our digestive tract, and form tears which cleanse our eyes.
   • 4. Medium for chemical reactions: Excellent solvent for many chemical reactions in body. This is because chemicals are more reactive in aqueous solutions than in solids. Needed in digestion to help break down food into smaller and simpler substances
   • 5. Transportation of nutrients: Important component in blood. 85% of blood made up of water. Blood needed to carry dissolved substances such as nutrients and oxygen to body cells and remove waste products such s carbon dioxide.

2. Sources: Water, soups, beverages and milk. Water can be found in fruit, vegetables, meat, seafood and poultry

3. Recommended daily intake: 1.5-2 litres (6-8 glasses)

4. Factors affecting water intake

   • i) State of health: People suffering from illnesses such as fever, cold, cough and diarrhoa lose more water from body. Thus, need to drink more water to replace loss. Pregnant women need to drink more water as water needed to form amniotic fluid which surrounds and protects the baby in the womb. Lactating women lose water thorugh breast-feeding. Hence, need to drink water regularly to replace water loss.
   • ii) Diet: Excessive intake of diuretics increases rate of urination in body, can result in excessive loss of water from body. (E.g. Coffee, tea, cola-flavoured drinks.) Thus, an increased intake of water is needed to replace the water lost through frequent urination
   • iii) Level of activity: More active people and those who engage in strenuous activities (vigorous exercise/manual labour) tend to perspire more and thus, require more water than those who are less active/sedentary.
   • iv) People living in hot and humid climate tend to perspire more easily. Thus, need to drink more water to replace water lost through perspiration. Body also tends to lose more water in cold and dry environment. Thus, an increased intake of water is necessary to prevent dehydration.

5. Insufficent intake: Lack of water can lead to dehydration. It occurs when body experiences an excessive loss of water. Symptoms include concentrated urine, weakness, dryness of mouth, throat and skin, confusion, nausea and overheating of body. Extreme cases can lead to heat stroke, coma and death. Result in hard and dry waste materials causing constipation. Person vwhose diet is high indietary fibre will need to consume more water to facilitate the easy remova; of waste materials from body.

   • Elderly and infants are at higher risk of dehydration, elderly tend to drink less water as their weakened senses make them feel less thirsty than they actually are. Infants lose more water because they urinate more frequently and are not able to tell that they are thirsty.

6. Excessive intake: May lead to water intoxication. Kidneys may not be able to work fast enough to get rid of excess water, causing blood to become diluted. If left untreated, can be fatal.